Patent GB-510153-A (GB)
Title: Improvements in apparatus for recording and reproducing sounds
IPC: G11B11/00
Filed: 1937-10-23
Abstract: 510,153. Sound recording and reproducing apparatus. MIA VOCE SOC. ANON. Oct. 23, 1937, Nos. 28950 and 28952. Convention dates, Oct. 24, 1936, and Oct. 1, 1937. [Class 40 (ii)] Apparatus for mechanically recording sound for optical reproduction, which apparatus is operatively associated with an ordinary wireless receiver in such a manner as to utilize amplifying stages thereof both for recording and reproducing, comprises a recording and reproducing unit 27 adapted to move transversely over an endless band 1 passing over a tensioning guide-roller 16 and a driving drum 15, the band being made of flexible transparent material coated with a thin layer of coloured gelatine or a coloured cellulosic substance, and the recorder having a stylus (shown in Fig. 6) comprising a fixed support 131 with a cylindrical recess receiving a vibrating cutting point 134 adapted to produce a sound track of constant width and varying depth. The point 134, the cutting edge of which passes through the axis 133 of the cylindrical recess, is connected by a rod 135 to the vibrating member of the electromagnetic recording head 47, which is of the type comprising a moving coil in the field of a permanent magnet. The head 47 is combined as a unit 27 with a reproducing head 46, which comprises a lamp in a housing 45 and an optical system 46a. A photo-electric cell 20 is located within the drum 15, which is transparent and which is rotated through gearing 23, 24 by a motor 25. A tube 26, arranged parallel to the drum 15, supports and guides the recording and reproducing unit 27. The tube 26 encloses a screw 28 (also driven by the' motor) for traversing the unit 27 by means of a nut 37 carried by a plunger 35 on 27, the plunger passing through a slot in the tube 26. The nut surrounds the screw 28, and has a tooth adapted to engage in either of two grooves in the interior of 26. so as to retain the unit 27 in position either for recording or for reproducing; the plunger can be withdrawn, to allow the position of 27 to be changed, by pressure on a button 41. Means are provided for making slight axial adjustment of the screw 28, to register the scanning beam exactly with the record. Switches (not shown) for making the required connections to the amplifier of a radio receiving set, are automatically operated when the unit 27 is moved to either of the positions necessary for recording and reproducing respectively, the switches comprising contacts on the unit 27 co-operating with contacts on the guide-tube 26. A threeposition switch on the radio set provides either for its normal use or for its use in connection with the sound-recording and reproducing apparatus. The Specification as open to inspection under Sect. 91 also describes apparatus for recording sound on an endless band consisting of any suitable flexible plastic material, with or without a coloured or other coating. the records being reproducible either electro-mechanically or electro-optically. Various kinds of chiseledged styli, having one or more cutting points. are described, for producing records intended for photo-electric reproduction. A machine in which both recording and reproducing are effected by means of a stylus device is shown in Fig. 14 (Cancelled). The endless band record carrier 1 passes round a drum 50 and a tensioning roller 52. the drum being driven by a motor which is also geared to a vertical spindle 55 carrying a member 58 on which is pivoted an arm 60. A "pick-up" 61, serving either for recording or reproducing. is carried by 60, and a stylus engages the band 1 above a support 71. A clutch 62 couples the members 55, 58 for recording, and can be disengaged when the pick-up is used for reproducing. by the action of a member 70 connected to a counterweight 67 inside the arm 60. When the weight 67 is moved back to effect declutching, the pressure of the stylus on the record is relieved. A turntable may be mounted on a squared spindle (not shown) driven by the motor. so that the machine may also be used with disc records. This subject-matter does not appear in the Specification as accepted.